1. Field of the Invention
The present invention relates to a magnetic head suspension for supporting a magnetic head slider that reads and/or writes data from and to a recording medium such as a hard disk drive, and also relates to a manufacturing method of the magnetic head suspension.
2. Related Art
Increase in capacity of a magnetic disk device requires improvement in accuracy for positioning a magnetic head slider on a target track. In this regard, there has been proposed a magnetic head suspension that enables coarse motion of a magnetic head slider in a seek direction by a main actuator such as a voice coil motor as well as micro motion of the magnetic head slider in the seek direction by a piezoelectric element functioning as a sub actuator.
For example, Japanese Unexamined Patent Application Publication No. 2002-050140 (hereinafter referred to as prior art document) proposes to provide a magnetic head suspension with the piezoelectric element with a following configuration in order to reduce a thickness in a direction orthogonal to a disk surface as much as possible.
More specifically, the magnetic head suspension disclosed by the prior art document includes a load bending part that generates a load for pressing the magnetic head slider toward a disk surface, a load beam part that transmits the load to the magnetic head slider, a supporting part that supports the load beam part via the load bending part and is swung about a swing center directly or indirectly by a main actuator, a flexure part that is supported by the load beam part and the supporting part while supporting the magnetic head slider, and paired right and left piezoelectric elements that is attached to the supporting part.
The supporting part is provided with a proximal end section that is connected directly or indirectly to the main actuator, a distal end section to which the load bending part is connected, an open section that is positioned between the proximal end section and the distal end section in a suspension longitudinal direction, and paired right and left connecting beams that are positioned on both sides of the open section in a suspension width direction and connect the proximal end section and the distal end section.
The piezoelectric elements are mounted to the supporting part, with use of a proximal end side-support plate and a distal end side-support plate that are respectively fixed to disk-facing surfaces of the proximal end section and the distal end section by welding, so as to be positioned within the open section in a plan view as viewed along a direction orthogonal to the disk surface.
More specifically, the distal end side-support plate includes a distal end side-fixed region that is fixed to the disk-facing surface of the distal end section in a state of being overlapped therewith, and a distal end side-supporting region that extends from the distal end side-fixed region so as to be positioned within the open section.
Similarly, the proximal end side-support plate includes a proximal end side-fixed region that is fixed to the disk-facing surface of the proximal end section in a state of being overlapped therewith, and a proximal end side-supporting region that extends from the proximal end side-fixed region so as to be positioned within the open section.
Under the configuration, the piezoelectric element includes a distal side-end surface and a proximal side-end surface that face a proximal side-end surface of the distal end section and a distal side-end surface of the proximal end section, respectively, with insulative adhesive agent being inserted between the respective facing surfaces, and a disk-facing surface having a distal side that is mounted on the distal end side-supporting region of the distal end side-support plate with insulative adhesive agent being inserted between them and a proximal side that is mounted on the proximal end side-supporting region of the proximal end side-support plate with insulative adhesive agent being inserted between them.
The magnetic head suspension with the configuration makes it possible to prevent as much as possible increase of thickness of the magnetic heads suspension due to provision of the piezoelectric elements, since the piezoelectric elements are mounted on the supporting part in a state where a least part of each of the piezoelectric elements is overlapped with the supporting part in the thickness direction.
However, the magnetic bead suspension leaves room for improvement in respect of fixing structure of a flexure metal plate of the flexure part.
More specifically, the flexure part includes the flexure metal plate welded to the disk-facing surfaces of the load beam part and the supporting part, an insulating layer such as a resin laminated on a disk-facing surface of the flexure metal plate, and a signal wiring formed by a conductive member that is laminated on a disk-facing surface of the insulating layer.
The flexure metal plate is fixed to the supporting part by welding at both sides of the open section in a suspension longitudinal direction. Here, the distal end side-support plate and the proximal end side-support plate are fixed to the distal side and the proximal side of the open section by welding, respectively, as explained above.
In other words, in the magnetic head suspension disclosed by the prior art document, a region of the flexure metal plate that is positioned on a distal side of the open section is welded to the fixed region of the distal end side-support plate as well as the distal end section of the supporting part while being overlapped with the disk-facing surface of the distal end side-support plate.
Similarly, a region of the flexure metal plate that is positioned on a proximal side of the open section is welded to the fixed region of the proximal end side-support plate as well as the proximal end section of the supporting part while being overlapped with the disk-facing surface of the proximal end side-support plate.
As described above, in the magnetic head suspension disclosed by the prior art document, at an area positioned on a distal side of the open section, three members inclusive of the flexure metal plate, the distal end side-support plate and the supporting part are overlapped with and welded to one another. At an area positioned on a proximal side of the open section, three members inclusive of the flexure metal plate, the proximal end side-support plate and the supporting part are overlapped, with and welded to one another. Resultingly, there is posed a problem that it is difficult to reduce the thickness and weight of the magnetic head suspension.
Moreover, since the three members are welded to one another, weld strength must be heightened, which results in a problem that a strain is likely to occur in the magnetic head suspension. The strain has a bad effect on floating posture of the magnetic head slider and vibration characteristics of the magnetic head suspension.